1. Field of the Invention
The present invention relates in general to the field of an intake and exhaust system of an internal combustion engine, and more particularly to an intake and exhaust system of an internal combustion engine that can achieve high-performance, high-power, low-vibration and an economical fuel consumption ratio by being engaged in proportion to engine load or a speed to supply a suction amount in standard quantity, dissipating pulsating energy inevitably generated during intake, reducing the exhaust resistance caused by interference with the exhaust gas during exhaust, and optimizing a fuel mixture ratio of the internal combustion engine.
2. Description of the Related Art
Generally, an intake and exhaust system sucks gases, which mix fuel with air, into a cylinder and discharges a combustion gas to the outside after the combustion of the mixed air.
The intake system mainly includes an air cleaner configured to remove a foreign substance such as dust from the intake air, a throttle valve configured to control a quantity of a sucked intake flow and an intake manifold configured to distribute mixed gases to respective cylinders. The exhaust system mainly includes an exhaust manifold configured to collect a combustion gas of the respective cylinders, and an exhaust pipe configured to discharge the combustion gas to the outside and a muffler.
Specially, the intake system may improve an engine's output by installing a variable intake system inside of the intake manifold so as to increase the suction efficiency according to engine load. This is a reason that the engine load/output is influenced if a quantity of mixed gases that is flowed to respective cylinders is unevenly supplied.
However, since the quantity of the intake flow is controlled by the throttle valve, the intake flow supplied at high speed reaches a pulsating state, i.e., a disproportion state of a pressure, resulting from either an intake resistance due to a pressure loss or an impact resistance due to an intake valve. This causes output deterioration of an engine and production of a noise, because new air is not sucked in sufficiently in proportion to the quantity of fuel. Moreover, the throttle valve is nearly closed during idling of the engine or partial load driving. At this time, a downstream side of the throttle valve is maintained in a high-degree vacuum state. This causes new air to be insufficiently sucked in, thereby deteriorating output of the engine. As a result thereof, environmental pollution is induced by incomplete combustion of exhaust gas.
Meanwhile, the exhaust system is gradually muffled by bringing on acoustic wave interference, a pressure change and a lower intake temperature while the exhaust gas passed through an exhaust pipe is passing through a multi muffler.
Specially, the exhaust process is smoothly performed, if a pressure in the cylinder is higher than that of the exhaust system in exhaust stroke. However, since exhaust pressure is higher than that of the cylinder due to exhaust resistance, if a high-performance muffler is applied so as to reduce the exhaust noise, the output of the engine is deteriorated.